Combined spring and friction shock absorber



ll-l. J. IFMQUNISURY 'COMBINED SPRING AND FRICTION SHOCK ABSORBER FiledMarch 29, 1959 3 SheetsfSheet l j l I /l// 1 ///I/7/ M. w W le April w1941- H. J. LouNsBURY L 2,238,227

`CDMBINED SPRING AND FRICTION SHOCK ABSORBER Filed March 29, 1939 3Sheets-Sheet 2 Harvey Ilaufzsz/)g 1 Hit H. J. RY

SPRING AND FKHCTION SHOCK ABSORBER Filed March `29 1939 3 Sheets-SheetE3 Patented Apr. 15, 1941 COMBINED SPRING AND FRICTION SHOCK ABSORBERHarvey J. Lounsbury, Glen Ellyn, Ill., assigner to W. H. Miner, Inc.,Chicago, Ill., a corporation of Delaware Application March 29, 1939,Serial N o. 264,704

5 Claims.

This invention relates to improvements in combined spring and frictionshock absorbers, especially adapted for use in connection with railwaycar trucks.

One object of the invention is to provide a shock absorbing unitcomprising a pair of relatively, longitudinally movable friction memberspressed into tight frictional contact by rocking movement toward eachother, through the action of spring means, wherein the friction membershave rocker base portions seated in relatively movable spring plates andthe spring plates and friction members have interengaing anchoring meansthereon to prevent separation of said members from the spring plates andalso restrict the extent of rocking movement of said members.

A more specific object of the invention is to provide a shock absorbingunit of the character specified in the preceding paragraph which isespecially adapted for use in connection with railway car trucks fordampening the action of the truck` springs.

Other objects of the invention will more clearly appear from thedescription and claims here-v after following.

In the drawings forming a part of .this speciication, Figure 1 is a topplan view of my combined spring and friction shock absorber. Figure 2 isa vertical sectional View, corresponding substantially to the line 2-2of Figure 1, showing the mechanism mounted between the bolster andspring plank of a railway car truck, the bolster and spring blank beingillustrated broken away. Figure 3 is a horizontal sectional view,corresponding substantially to the line 3-3 of Figure 2. Figures 4, 5,and 6 are front, side, and rear elevational views, respectively, of oneof the friction members of the improved shock absorber. Figure 7 is asectional view, similar to Figure 3, and corresponding substantially tothe line 1-1 of Figure 8, illustrating another embodiment of theinvention. Figure 8 is a vertical sectional View, correspondingsubstantially to the line 8 8 of Figure 7.

In said drawings, referring more particularly to Figures 2 and 8, I0indicates the truck bolster and Il the spring plank of the truck of arailway car to which my improvements are applied, the improved combinedspring and friction shock absorber being interposed between said truckbolster and spring plank.

Referring first to the embodiment of the invention illustrated inFigures 1 to 6 inclusive,

by improved combined spring and friction shock absorber comprisesbroadly top and bottom spring plates A and B, four spring units C`C-C--C; and a pair of friction elements D-D, said friction elements andspring plates having c0- operating anchoring means thereon.

The top and bottom spring plates A and B are of similar design, eachbeing of substantially rectangular outline and having rounded corners,as shown most clearly in Figure 1. Each spring plate is provided with asubstantially rectangular opening l2 therethrough, providing a seatadapted to accommodate the base portion of one of the friction elementsD, as hereinafter more fully described. The openings l2|2 of the top andbottom spring plates are respectively located at opposite sides of avertical plane coincident with the vertical central axis of themechanism. Each plate is provided with the usual inwardly projectingspring centering bosses i3-l3-l3l3 indicated in dotted lines in Figures1 and 2. These bosses are four in number and are spaced symmetricallyabout the central vertical axis of the mechanism. The spring plates Aand B are exact duplicates, being reversely arranged so that theopenings or seats l2-l2 thereof are located at opposite sides of l thevertical central axis of the mechanism.

The springunits C---Cl--C-Cl preferably correspond in size and capacityto the units of `the usual truck spring cluster of a railway car truckand in actual practice the standard spring units of a four springcluster are employed. Each spring unit C comprises a relatively heavyouter coil and a lighter inner coil, the coils being interposed betweenthe spring plates A and B with the inner coil of the unit centered bythe corresponding bosses |3-l3 of the top and bottom plates A and B.

The friction elements D-D are of like design, each being in the form ofa casting comprising a postlike plate member I4 having a laterallyprojecting base iiange or foot I5 at one end thereof. On the inner side,the plate or post member I4 of each element D is provided with arelatively wide, nat friction surface I6. As will be seen upon referenceto Figures 1, 2, 5, and 6, the projecting base iiange or foot member l 5extends from the side of the friction element opposite to the frictionsurface IG thereof. The angle between the friction surface IE and thebottom face of the foot member l5 is slightly in excess of a rightangle, as clearly indicated in Figures 2, 3, and 5, whereby saidfootmember I5 is slightly inclined to the horizontal when the parts areassembled, thus providing for rocking lever action of the foot member onits support. The post or plate member i4 is cut away at opposite sides,as indicated at l'l-VL to clear the corresponding pair of spring unitsC-C, as clearly shown in Figures 1, 3, and 6, the cut away portionsbeing provided with inwardly curved surfaces corresponding with thecurvature of the outer coils of the spring units C-C. The posts or platemembers of the friction elements D--D thus are broadly of substantiallytriangular, transverse cross sectional outline.

The two friction elements D-D of the shock absorber have the frictionsurfaces l-l thereof in fiat engagement and said elements are reverselyarranged end for end, that is, with the base flange or foot member l5 ofone of the elements D at the bottom of the mechanism and the base flangeor footl member l5 of the other element D at the tcp of the mechanism.The base members l5-l5 are respectively seated in the openings EZ-IZ ofthe top and bottom spring plates A and B. The shape of the base flangesIii-l5 is such as to t the openings IZ-IZ of the plates A and B, thatis, they are of rectangular outline to seat in said openings, butsuihcient clearance is provided between each base member and the sideand end walls of the seat to allow the base member to have relativelyfree rocking movement within the seat. The

springs C-C-C--C overlap the base members f I5-I5, one pair of springsC-C overlapping the base member l5 of one of said friction elements andthe other pair of springs C-C of the cluster overlapping the base memberl5 of the cooperating friction element. As will be evident, the basemembers of the friction elements D-D are thus subjected to the pressureof the springs and the tendency is to rock the friction elements towardcach other to press the .friction surfaces thereof into tight frictionalengagement.

The top and bottom spring plates A and B bear respectively on theunderneath surface of the truck bolster lll and the top of the springplank l I. The base portions lE-IE of the friction elements D-D engagethrough the openings |2-l2 of the spring plates A and B and bearrespectively on said bolster and spring plank. The friction elements D-Dare thus heid in tight frictional engagement with each other by thesprings C-C due to the leverage action of the base members i-IS whichhave rocking engagement at their outer ends with the cooperating facesof the truck bolster and spring plank. The post or plate member I4 ofeach friction element D is of lesser height than the distance betweenthe spring plates A and B at the time that the springs C-C-C-C are inthe expanded position shown in Figure 2. The upper end of the lowerfriction element D and the lower end of the upper friction element D arethus normally spaced from the inner sides of the top and bottom springplates A and B, respectively. The clearance thus provided is sufficientlto permit of the required compression of the springs C-C-C-C in service.

To prevent accidental separation of the friction elements D--D from thespring plates A and B. when the mechanism is assembled, each element Dis provided with a lug I8 cooperating with a retaining member or lip I9formed on the corresponding spring plate. As shown most clearly inFigures 2, 3, 4, and 5, the retaining lug I8 is relatively wide andprojects at right angles from the front side of the platelike postmember of the friction element D and is located near the foot endthereof. As shown in Figure 2, the lug i8 extends in a directionopposite to the foot l5 and overhangs the metal of the spring plate atthe opening l2 of said plate. As shown, suiiicient clearance is providedbetween the lug I8 and the adjacent surface of the spring plate topermit the required rocking movement of the friction element, butprevent excessive outward displacement of the friction element throughthe spring plate when said plate is removed from contact with either thebolster or spring plank, as the case may be. The retaining member IS isof hook-shaped vertical cross section, as clearly shown in Figure 2, andcomprises an outstanding web 2S at right angles to the inner face of.the corresponding spring plate A or B, and an angular extending lip 2lprojecting from said web and ovcrhanging the lug E3 of the correspondingfriction element D. As shown most clearly in Figures 2 and 5, the frontface of the friction element is cut away for a short distance, inwar lyof the lug i3, thereby providing an inset surface 22 beyond the frictionsurface It of said element. As will be evident, the cooperating frictionsurface portions IG-IB of the two friction members D-D being thus raisedwith respect to the remaining surface portions of said friction surfacesallow for a maximum amount of wear of `the friction surfaces withoutdanger of the outer end portion of one friction element gouging into thefriction surface of the other element.

The operation of improved mechanism shown in Figures 1 to 6 inclusive isas follows: Upon relative approach of the spring plank and truckbolster, the coils of the group or cluster of springs C-C--C--C arecompressed between the plates A and B. At the same time, the frictionelements D-D are forced to slide relatively lengthwise on each other,being actuated respectively by the spring plank and bolster. A frictionsnubbing action is thus produced during compression of the springs.During recoil of the springs, the friction elements are returned to thenormal position shown in Figure 2, the base members iii-i5 of thefriction elements being moved outwardly away from each other with thespring plates by the recoil of the springs. The recoiling action of thesprings is dampened or snubbed by the friction elements D-D which areheld in tight frictional engagement through the spring pressure actingon the rocking arm or base portions of the friction elements. As will beevident, as the springs are being compressed the frictional resistanceproduced by the relative movement of the elements D-D is augmented dueto the increased pressure of the springs on the arms or base portionsl5-I5. As the springs recoil, the frictional resistance is progressivelyreduced due to the reduction of the spring pressure on the rockingfriction elements.

The retaining means, comprising the retaining lugs I8-l8 and hook-shapedretaining members IEP-l, serves to prevent :accidental displacement ofthe parts with respect to each other in service which might result nbinding of the friction elements, by preventing each friction element Dfrom being displaced either upwardly or downwardly with respect to theassociated -spring plate to an extent which would permit :the foot I5 tobe unseated from the opening I2.

For example, in the event that the top spring plate accidentally dropsaway from the bolster or the bottom spring plate accidentally jumpsupwardly with respect to the spring plank, due to the car beingsubjected to violent` jars, my improved retaining means successfullymaintains the friction elements inv proper operative position becauseofthe limited bodily displacement permitted between each frictionelement and the associated spring plate by said retaining means.

` Referring to the embodiment of the invention illustrated in Figures 7and 8, the improved friction shock absorber comprises top and bottomspring plates F and G, four spring units H-fII-HH; and a pair offriction elements K-K, and cooperating anchoring means on the springplates and friction elements, which anchoring means is of a differentcharacter than that disclosed in Figures 1 to 6 inclusive.

`The top and bottom spring plates F and G are of similar design, eachbeing of substantially rectangular outline and having rounded cornerssimilar to the spring plates A and B hereinbee fore described. Eachspring plate is provided with a substantially rectangular opening H2therethrough, providing a seat adapted to accommodate the base portionof one of the friction elements K in a manner similar to the frictionelement D, hereinbefore described. The openings IIE-I I2 of the top andbottom spring plates are respectively located at opposite sides of avertical plane coincident with the vertical central axis of themechanism. These plates bear on the top and bottom ends of the springunits H-H-H-H which are interposed between the plates. The spring unitsI-I--He-H-H are in all respects C-CCC, hereinbefore described, and areheld centered by bosses II3 on the spring plates identical with thebosses I3 of the spring plates A and B.

The friction elements K-K are of like design, each being in the form ofa casting comprising a postlike member I I4 having a laterallyprojecting base flange or foot II5 lat one end thereof corresponding tothe foot I5 of the friction member D, hereinbefore described, andarranged and operating in a similar manner. On the inner side, that is,the side remote from the foot II5 of the friction member, the plate orpost IM of the element K is provided with a relatively wide, flatfriction surface IIB. The post or plate member II4 is cut away atopposite sides, as indicated at II'l--II'I to clear the correspondingpair of spring units I-I-I-I in a manner similar to the post of thefriction member D, hereinbefore described.

The friction elements K-K are similarly arranged to the frictionelements D-D of the embodiment of the invention illustrated in Figures 1to 6 inclusive and operate in a similar manner, the friction surfaces IIG-I IB of the friction elements K-K being in sliding contact with eachother and pressed together by the rocking action of said elements underpressure of the springs I-I-I-I-H-H.

The upper end of the lower friction element K and the lower end of theupper friction element K are normally spaced from .the inner sides ofthe top and bottom spring plates F and G, respectively. The clearancethus provided is suincient to permit the required compression of thesprings H-l-I-H-H in service, without the springs going solid. Thesprings are prevented from l.being unduly compressed and going solid byengagement of the ends of the friction elements K--K with the respectivespring plates,

similar to the units the friction elements serving as column members tosustain the load.

To prevent accidental separation of the friction elements K--K from thespring plates F and G, when the mechanism is assembled, each springplate is provided with an anchoring lug or lip H9 having shoulderedengagement with the corresponding friction element K to restrict upwardand downward movement of said element with respect to the plate. Asshown in Figures 7 and 8, the lug or lip IIQ of each plate overhangs theopening H2 of said plate and is of the general outline in plan, as shownin Figure '7. The lug of the bottom plate G is offset upwardly withrespect to the plane of said plate and the lug of the top plate F isoffset down-- wardly as clearly shown in Figure 8. The postlike memberII 4 of each friction element is provided with a vertical core openingIZll, the core opening of the post of the bottom friction element Kbeing partly closed at its lower end by a horizontal web or shelf I2Iwhich serves as a shoulder cooperating with the lug IIS of the springplate G, and the core opening of the post of the top friction elementbeing partly closed at its upper end by a like web IZI cooper ating withthe lug IIB ofthe spring plate F. The wall of the core opening at thefriction face side of the post of each friction element K is cut away orslotted, as indicated at |22, to accommodate the lug II 9 of theYcorresponding spring plate. The upper wall of the slot of the post ofthe bottom friction element K and the bottom wall of the slot of thepost of the upper friction element K provide limiting shoulders I23--I23cooperating with the lugs IIS- I I9 of the plates G and F. As shown,suflicient clearance is provided between the lug IIS of each springplate and the shoulder I 23 of the corresponding friction element topermit the required rocking movement of the friction element, butprevent excessive outward displacement of the friction element throughthe spring plate when the plate is removed from contact with either thebolster or the spring plank, as the case may be. Engagement between thelug IIS of the spring plate with the shoulder formed by the web I 2| ofthe corresponding friction element prevents relative movement in avertical direction of these parts, to an extent which would permit thefoot of the friction element to leave its seat in the spring plate.

I have herein shown and described what I now consider the preferredmanner of carrying out my invention, but the same is merely illustrativeand I contemplate all changes and modifications that come within thescope of the claims appended hereto.

I claim:

l. In a shock absorber, the combination with a pair of relativelymovable-friction elements in lengthwise sliding frictional contact witheach other and interposed between a pair of relatively movable members,said elements having base portions in rocking bearing engagementrespectively with said members and directly actuated to slide relativelyto each other by engagement with said members; of plates having openingswhich said base portions are seated, said plate members bearing on saidrelatively movable members respectively; cooperating retaining means oneach friction element and associated plate for limiting relativedisplacement of the same to retain the base portion of said elementseated in said plate; and spring means interposed between said platesand having bearing engagement with said base portions of said elementsrespectively `for rocking both of said elements and pressing the latterinto tight frictional contact, said spring means directly resistingrelative longitudinal movement of said friction elements toward eachother and holding said base portions seated on said members and therebyrelieving said retaining means from actuating strains.

2. In a shock absorber interposed between two relatively movable membersto yieldingly resist relative approach thereof, the combination withopposed spring plates bearing on said members respectively, each platehaving an opening therethrough; of a pair of friction elements inlengthwise sliding engagement with each other, each element having arocker base portion integral therewith, said base portions being seatedin the openings of said plates respectively and having rocking bearingengagement with said members; cooperating anchoring means on eachfriction element and associated plate comprising a lug on one of thesame and a lip on the other overhanging said lug; and springs interposedbetween and engaging said spring plates and overlapping said baseportions of the friction elements to rock the latter into tightfrictional engagement with each other and yieldingly oppose relativesliding movement of said elements and force said elements apartlengthwise, thereby relieving the anchoring means from strain.

3. In a shook absorber interposed between two relatively movable membersto yieldingly resist approach thereof, the combination with opposedinterengaging, relatively lengthwise slidable friction elements, eachhaving an elongated friction plate element provided with a base flangeat one end, said friction plates being in face to face contact and thebase flange of one of said elements being in rocking engagement with oneof said members, and the base flange of the other plate being in rockingengagement with the other member; of spring plates surrounding said baseflanges of said elements respectively and bearing respectively on saidmembers; a projecting anchoring lug on each friction element at the endportion thereof which has the base flange, said lug being spacedinwardly from said end of said element and overhanging the body of theassociated spring plate in slightly spaced relation thereto; a retaininghook on the associated spring plate extending over said lug and normallyout of contact therewith; and springs interposed between said springplates and bearing y on said base flanges of said elements for rockingthe friction plates thereof into tight frictional engagement with eachother and yieldingly resisting relative sliding movement of saidelements toward each other.

4. In a shock absorber adapted to be interposed between two relativelymovable members, the combination with a pair of opposed, spaced,relatively movable spring plates, each plate having an openingtherethrough, the opening of one plate being disposed at one side of thecentral longitudinal axis of the device, and the opening of the otherplate being disposed at the opposite side of said axis; of a hookedretaining member on each plate adjacent the inner side of the openingthereof; a pair of friction elements, each comprising a base portion andan upstanding post on said base portion, said post of said elementsbeing in sliding frictional bearing engagement with each other, one ofsaid elements having the base flange thereof seated in the opening ofone of said spring plates and the other element having its base flangeseated in the opening of the other plate; a lug on the post of eachfriction element adjacent the base portion thereof but spaced inwardlyfrom said base of said element, said lug of each element overhanging thebody of the associated spring plate and projecting into the spacebetween said plate and the hook of the retaining element of said plate;and springs interposed between said spring plates and bearing on thebase anges of said elements for rocking the latter intotight frictionalengagement and yieldingly holding said base portions seated on saidmembers throughout normal actuation of the mechanism.

5. In a shock absorber interpsed between two relatively movable membersto yieldingly resist relative approach thereof, the combination withopposed, relatively, longitudinally movable friction elements in slidingcontact with each other, each element being slotted and having a baseportion in rocking engagement with the corresponding movable member; ofspring plates bearing on said members respectively, each spring platehaving an opening therethrough in which the base portion of one of saidelements is seated; springs interposed between said spring plates, saidsprings pressing the base portions of the friction elements to rock saidelements into frictional contact with each other; and a lug on eachspring plate overhanging the opening of said plate and extending intothe slot of the corresponding friction element to anchor said element tothe plate for restricted relative movement HARVEY J. LOUNSBUR

